My PC starts up but I get "No Signal" on display

Hey!

Okay. So I've researched for the past few days and figured all my mistakes (using HDMI). I just built this PC (specs below) and I tried everything to show something on the screen. All I get is a "No Signal" error. I've tried moving the RAM (only have 1 stick) and I've checked that nothing is damaged. When I connect the PC and turn it on, all the motherboard and fan lights turn on.

Also, I'm using VGA (before, I was using HDMI) and it doesn't connect to my video card (only supports HDMI and DVI). I've tried everything to fix this from removing the video card and trying but nothing works.

It's a brand new PC so I don't think I need to dust it or there's any dust issues. It looks completely dust-free.

Another thing is that I haven't connected some cables from my power supply to my motherboard or any components (like extra drive cables). Is that something I should worry about?

Here are my specs:
Asus Prime B350 Plus MotherBoard
AMD Ryzen 5 1600X
Wraith Spire Max Cooler
Zotac GTX 1050Ti
1x 16GB Ballistix DDR4 RAM
Corsair VS550 Power Supply
Barracuda 2TB SATA
Kingston 120GB SSD